Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str., 16/10, 117997 Moscow, Russia; Moscow Institute of Physics and Technology (State University), Department of Physicochemical Biology and Biotechnology, Institutskii per., 9, 141700, Dolgoprudny, Moscow Region, Russia.
Biochem Biophys Res Commun. 2013 Oct 4;439(4):427-32. doi: 10.1016/j.bbrc.2013.08.078. Epub 2013 Aug 31.
Lipid transfer protein, designated as Lc-LTP2, was isolated from seeds of the lentil Lens culinaris. The protein has molecular mass 9282.7Da, consists of 93 amino acid residues including 8 cysteines forming 4 disulfide bonds. Lc-LTP2 and its stable isotope labeled analogues were overexpressed in Escherichia coli and purified. Antimicrobial activity of the recombinant protein was examined, and its spatial structure was studied by NMR spectroscopy. The polypeptide chain of Lc-LTP2 forms four α-helices (Cys4-Leu18, Pro26-Ala37, Thr42-Ala56, Thr64-Lys73) and a long C-terminal tail without regular secondary structure. Side chains of the hydrophobic residues form a relatively large internal tunnel-like lipid-binding cavity (van der Waals volume comes up to ∼600Å(3)). The side-chains of Arg45, Pro79, and Tyr80 are located near an assumed mouth of the cavity. Titration with dimyristoyl phosphatidylglycerol (DMPG) revealed formation of the Lc-LTP2/lipid non-covalent complex accompanied by rearrangements in the protein spatial structure and expansion of the internal cavity. The resultant Lc-LTP2/DMPG complex demonstrates limited lifetime and dissociates within tens of hours.
从菜豆种子中分离出一种脂质转移蛋白，命名为 Lc-LTP2。该蛋白的分子量为 9282.7Da，由 93 个氨基酸残基组成，包括 8 个半胱氨酸形成的 4 个二硫键。Lc-LTP2 及其稳定同位素标记类似物在大肠杆菌中过表达并纯化。检测了重组蛋白的抗菌活性，并通过 NMR 光谱研究了其空间结构。Lc-LTP2 的多肽链形成四个α-螺旋（Cys4-Leu18、Pro26-Ala37、Thr42-Ala56、Thr64-Lys73）和一个没有规则二级结构的长 C 末端尾巴。疏水性残基的侧链形成一个相对较大的内部隧道样脂质结合腔（范德华体积高达约 600Å(3)）。Arg45、Pro79 和 Tyr80 的侧链位于假定的腔口附近。用二肉豆蔻酰磷脂酰甘油（DMPG）滴定表明形成了 Lc-LTP2/脂质非共价复合物，同时伴随着蛋白质空间结构的重排和内部腔的扩张。所得的 Lc-LTP2/DMPG 复合物具有有限的寿命，并在数十小时内解离。
